Dynamics of the photo-induced orientation and relaxation of new polymethacrylates containing carbazolyl and azobenzene pendant groups

✍ Scribed by Maertens, Christophe; Dubois, Philippe; Jerôme, Robert; Blanche, Pierre-Alexandre; Lemaire, Philippe C

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 227 KB
• Volume: 48
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199903)48:3<205::aid-pi92>3.0.co;2-l

✦ Synopsis

Polarized-light-induced birefringence has been investigated in copolymers of [ x-(Ncarbazolyl)alkyl methacrylate ] and [ 2,5-dimethylphenyl-[ (4-nitrophenyl)azo ] phenoxyalkyl methacrylate ] . Optical properties of the side-chain copolymers have been compared with materials in which the azo-dye was merely dispersed in a poly [ x-(N-carbazolyl)alkyl methacrylate ] matrix. Increasing the temperature of the ülm has a dramatic depressive eþ ect on the maximum of photoinduced orientation near and above the glass transition temperature region, while its eþ ect was (T g ) restricted under this temperature. Kinetics of the photo-orientation and the thermal relaxation as a function of temperature have been analysed by a biexponential model based on two rate constants. The universal Williams-Landel-Ferry (WLF) theory has been used to correlate the writing process and relaxation relative time constants with the relative temperature, i.e. The validity of this T Ô T g . model for the studied materials leads to the assumption that photo-orientation and relaxation processes are mainly dependent on the free volume in the polymer matrix. This hypothesis has been assessed in the case of [ 11-(N-carbazolyl)undecyl methacrylate ] -based materials.